Post-maximally preaerated hydrocarbons and processes for their manufacture



3,549,708 -MAXIMALLY PREAERATED HYDROCARBONS AND PROCE SSES Dec. 22, 1970 c, NORTON l-Tl'AL POST FOR THE IR MANUFACTURE 2 Sheets-Sheet 1 Filed Sept. 15, 1966 o3 08 e8 02 08 08 89 0O.

OON

HHEIWI'IN HCIIXOHHd t 8565 us; On ON O O aaawnu aolxoaad INVENTORS CHARLES J. NORTON y MICHAEL J. REUTER 1970 c, J, NORTON ETAL- 3,549,708

POSTMAXIMALLY PREAERATED HYDROCARBONS AND PROCESSES FOR THEIR MANUFACTURE Filed Sept. 15, 1966 2 Sheets-Sheet 2 mmmzaz m xommm 8m maoaad awn'loflwolsaamoo o o l 9 8 zoEood l on O 0 8: m l ow M 0 4 N N oo-r l on W n W 3 m l w H 08 m N Oh com zo mw mmn l 8 ST HBHWHN EIGIXOHBd INVENTORS CHARLES J. NORTON MICHAEL J. REUTER United States Patent 01 fice 3,549,708 Patented Dec. 22, 1970 3,549,708 POST-MAXIMALLY PREAERATED HYDRO- CARBONS AND PROCESSES FOR THEIR MANUFACTURE Charles J. Norton, and Michael J. Renter, Denver, and Ned F. Seppi, Littleton, Colo., assignors to Marathon Oil Company, Findlay, Ohio, a corporation of Ohio Filed Sept. 15, 1966, Ser. No. 579,561 Int. Cl. C07c 73/06 US. Cl. 260-610 9 Claims ABSTRACT OF THE DISCLOSURE Contacting hydrocarbons with oxygen-containing gases until a maximum peroxide number as specified herein is reached and thereafter continuing to contact said hydrocarbons with oxygen-containing gases until said peroxide number is decreased.

The present invention relates to new activated forms of compounds prepared by contacting hydrocarbons with oxygen and in particular relates to the products formed by contacting hydrocarbons with oxygen-containing gases until a maximum peroxide number as specified herein is reached and thereafter continuing to contact said hydrocarbons with oxygen-containing gases until said peroxide number is decreased.

As taught by our copending application Ser. No. 520,632 assigned to the same assignee, the contacting of olefins and other unsaturated hydrocarbons with oxygen-containing gases enhances later reaction of such hydrocarbons with bisulfites and similar addition reagents.

The present invention embodies the surprising discovery that the activity of such preaerated hydrocarbons can be even further enhanced by first preaerating to a maximum peroxide number as defined herein and thereafter continuing to preaerate. Such continued preaeration has been discovered to actually decrease the peroxide number of such hydrocarbons but to simultaneously increase their activity in addition reactions.

In summary, the present invention comprises hydrocarbons containing at least one unsaturated bond and one allylic hydrogen which have been preaerated by contact with an oxygen-containing gas until a maximum peroxide number has been obtained and thereafter further preaerated so as to decrease the peroxide number to not less than about and processes for their preparation.

While the present invention can be utilized with a wide variety of hydrocarbons containing at least one unsaturated bond and one allylic hydrogen, hydrocarbons which contain only one or two such allylic hydrogens are more preferred. Also, the olefin form of unsaturated hydrocarbon is preferred for the reactions of the present invention. Most preferred as starting materials for the present invention are alpha-olefins such as those having carbon numbers of from about C to about C with carbon numbers of about C through C being especially preferred.

Examples of the hydrocarbons having at least one allylic hydrogen which may be utilized with the present invention are olefins, e.g. cyclohexane; alpha-, omega-hexadiene, 2,6-octadiene, 2,18-eicosadiene, 2-methy1-3-hexene, S-decene and alpha-olefins such as l-hexene, 3-methyl-1-hex ene, l-decene, l-hexadecene. The principal source of many of such raw materials will be thermally cracked petroleum streams, shale oils, synthetic hydrocarbon mixtures, etc., many of which are particularly rich in straight chain mono-olefins and are therefore preferred for the purposes of the present invention. Mixtures of any of the above may be employed.

Air is the preferred oxygen-containing gas, but other streams containing oxygen with inert gases and also pure oxygen can be employed.

The products of the present invention are particularly preferred for further reaction with radical addition type reagents such as acetic acid; sodium bisulfite or other alkali metal bisulfites; inorganic phosphites e.g. sodium phosphite (Na HPO inorganic hypophosphites, e.g. sodium hypophosphite (NaH PO organic derivatives of phosphite and hypophosphite, particularly those which contain lower valencies of phosphorous with at least one hydrogen on the phosphorous; various organic reagents having at least one hydrogen alpha to an unsaturated center, e.g. a double bond, a ketone group, or a hetero atom having at least one pair of unshared electrons such as oxygen, nitrogen, halogen or sulfur. Examples of such organic compounds are olefins themselves, e.g. the above mentioned olefins; lactones, e.g. gamma butyrolactone, lactams, e.g., caprolactam, and anhydrides, e.g. acetic anhydride; ethers, e.g., diethyl ethers, primary and secondary alcohols, such as l-butanol and 2-butanol, ethyl and isopropyl alcohol; inorganics such as H S, mercaptans such as butyl mercaptan, ethyl mercaptans and alkyl aromatics having at least one hydrogen atom alpha to the benzene ring.

In addition to using the in situ preaeration products as catalysts for reacting the preaeration mixture per se with the reagents mentioned above, they may also be employed in relatively small amounts to activate reactions between other compounds. This quantity of preaerated olefins contains from about 0.5 meq. to about 400 meq., more preferably 0.5 to about 40 meq. and most preferably 1.5 to about 20 meq. of titratable peroxide by Method I. For example, a quantity of post-maximally preaerated product can be added to the reaction mixture to activate or otherwise enhance a wide variety of reactions including polymerization reactions such as those of styrene, methylstyrenes, vinyl monomers, e.g. vinyl chloride, vinyl acetate, acrylates such as methyl methylacrylate production, acrylonitrile monomers, isoprene and butadiene monomers, and similar polymerization reactions.

In the preparation of the products of the present invention, the air or other oxygen-containing gas must be intimately contacted with the hydrocarbons to be preaerated, preferably by sparging in the gas to a suitable diffuser, e.g. alundum, sintered glass, or inert perforated pipe. Normally, the agitation provided by the air will be sufficient, but in some cases, results can be improved by mechanical agitation, e.g. by stirring or shaking or, particularly preferred, the high shear agitation such as that provided by contra-rotating stirring devices.

The temperature during the aeration, while not narrowly critical, must be above the freezing point of the hydrocarbons and should be sufficiently low so as not to excessively deteriorate the starting materials or the products formed during preaeration. In general, temperatures of from about the melting point of the hydrocarbons to about 325 C., more preferably from 50 to about 200 C., and most preferably from to about C. will be employed.

Likewise, pressure during the preaeration step is not critical and can range from about 0.1 to about 10,000 atmospheres absolute with pressures of about 1.25 to about 1000 atmospheres absolute being more preferred, and pressures of about 2 to about 20 atmospheres absolute being most preferred. It is important that the explosive ranges of hydrocarbons with oxygen be avoided during the preaeration. Explosive conditions can readily be detected by conventional explosimeters and corrected by varying the rate of flow of the oxygen-containing gas or its concentration in the reactor.

The preaeration may be conducted in the presence of solvents which are inert under the conditions of the reaction; but in general, undiluted hydrocarbon raw materials will be preferred. The concentration of the preaerated product may be diluted with unaerated hydrocarbon or inert solvent.

The reaction times of the preaeration step will vary with the types of hydrocarbon raw materials employed and with the temperature, pressure and rate of flow of oxygen-containing gas. In general, preferred reaction times will be from about 0.01 to about 100 hours with times of from about 0.1 to about hours being more preferred.

Wherever peroxide number is mentioned herein, unless otherwise noted, this phrase refers to the number obtained by a peroxide number determination by iodometric titration with sodium thiosulfate. (The number of mili-equivalents Na S O required to titrate one kilogram sample of the preaerated product) by Hercules Method I of [Mair, R. D. and Graupner, Alda 1., Determination of Organic Peroxides by Iodine Liberation Procedures,

Analytical Chemistry, vol. 36 N0. 1, pp. 199-204 (Jan- I uary, 1964).] It should be noted that the above article gives three titration methods. Method I has been found to give a sharper maximal inflection point and is much preferred for control purposes. While the other titration methods may be useful in continuing research into the reaction mechanisms, they sometimes will give no maximum point at all and are therefore much less suitable for control of the preaeration reaction.

While it should be understood that the present invention is in no way restricted to any particular hypothesis or theory of operation, it appears that peroxide numbers prior to the maximum are probably largely due to the formation of hydroperoxides and that after the maximum point these hydroperoxides may be substantially converted to polymeric peroxides. In this connection it is noted that peroxide numbers determined by Method III rather than by Method I continue to increase, apparently indicating that the total content of peroxide in compounds continue to increase after the maximum peroxide number as defined herein according to Method I is reached. Preaerated compositions having Method III peroxide numbers in the general range of from about 300 to about 2500, more preferably 600 to 2000, and most preferably 900 to 1600 are especially desirable so long as the compositions also fall within the above specified ranges for peroxide number as determined by Method I.

This peroxide number titration is the primary control method employed in the manufacture of the products of the present invention. In practice, the hydrocarbons are placed in a suitable reaction vessel and are intimately contacted with oxygen-containing gas as discussed above.

Peroxide number titrations are run on samples taken at intervals during the preaeration process. The peroxide number will be found to gradually increase until a maximum point is reached. Surprisingly, this maximum point is not indicative of preaerated olefins having the highest activity. Higher activities are achieved, according to the present invention, by proceeding past this maximum point and continuing to preaerate. Such continued preaeration causes the peroxide numbers to gradually decrease, but such post-maximally preaerated hydrocarbons have been found to have even higher activities both as reactants and as reaction activators than do hydrocarbons which have not been preaerated further after the maximum peroxide number has been achieved.

In general, the amount of post-maximal preaeration will be optimized according to the conversions which are obtained at various levels of post-maximal peroxide number when such preaerated hydrocarbons are used as reactants or as reaction enhancement agents. However, the preferred range of post-maximal peroxide numbers will, in general, be from about 90% of the maximum value down to peroxide numbers of about with post-maximal peroxide numbers of from about 75% of the maximum value down to about peroxide number being more preferred.

Since the peroxide number, as determined above, is a relative figure which varies somewhat according to the molecular weight of the hydrocarbons being preaerated, no absolute level of optimum post-maximum peroxide number can be given. However, most maximum peroxide numbers will fall in the range of from about 200 to about 500 and these are readily found for particular hydrocarbons and conditions involved by taking samples at intervals until the peroxide number stops increasing. Generally, the most desirable post-maximal peroxide numbers will fall in the range of from about 375 down to about 100.

Preaerated olefins retain their reactivities for period of several months when stored at ambient temperatures.

The apparatus for the present invention can be conventional batch or flow equipment inert under the reaction conditions, preferably a stirred sealed autoclave, with air sprayer and vent for excess gases, e.g. nitrogen. Preferred materials of construction are inert resin or plastic coatings, glass, glassed steel, heat alloy, and stainless steel. Copper is generally objectional.

The present invention will be more fully understood by reference to the examples which follow. However, it should be understood that the invention is susceptible to a wide variety of modifications and variations which will be obvious to those skilled in the art upon a reading of the present specification. All such modifications and variations are to be taken as included within the scope of the claims appended hereto.

EXAMPLE I Batch preaeration of alpha-olefins Alpha-olefins can be preaerated for 30 hours at C. to give effective postmaximal peroxide mixtures with the optimum mixture occurring past the maximum titer of about 200-230 milliequivalents Na S O per kg. of olefin sample determined as described herein.

500 ml. of hexadecene-l are placed in a 1-liter flask and heated to 110 C., controlled by a thermowatch. The mixture is stirred by a Heller stirrer with a glass shaft and Teflon blade to disperse the air which is introduced through an air sparger. The air flow is controlled at about 80 cc./min. (70 F. and 14.7 p.s.i. absolute) with a rotameter equipped with a diameter glass ball. The peroxide number vs. time curve for the preaerated l-hexadecene is shown in FIG. 1. Under these conditions, postmaximal peroxide compositions are obtained after about 16 hours preaeration at 110 C.

EXAMPLE II Batch preaeration of internal olefin A sample of Chevron Chemical Co. C C isomerized alpha-olefins are preaerated by the procedure of Example I. This mixture of predominantly internal olefins reacts to give larger peroxide numbers than the mixture of Chevron alpha-olefins containing predominantly terminal double-bonds. For example, a postmaximal peroxide number of 413 was obtained after nineteen hours preaeration at 110 C.

EXAMPLE III Batch preaeration of alpha-olefins in a Fischer-Porter Bottle 44.88 g. (0.200 mole) hexadecene-l is weighed into a Fischer-Porter bottle. The bottle is flushed ten times with 0 from 110 p.s.i.g. reservoir and immersed in an oil bath preheated and controlled at J l C. A constant pressure diaphragm valve is equilibrated at 9 p.s.i.g. total overpressure above the vapor pressure of the hexadecenel. The stirred hexadecene-l is reacted for the time indi- Continous preaeration of Chevron -0 alpha-olefins A ten gallon glass-lined Pfaudler reactor equipped with Milton Roy inlet and outlet pumps, tantalum heat exchanger, Dry Ice trap, dry gas meter, and temperature controller is charged with 34.4 lb. Chevron C -C alphaolenfins and a lb. seed of previously preaerated alphaolefins (total 6 gallons). The reactor is heated with steam in a steam jacket to 130 C. with maximum agitation (275 r.p.m.). At temperature, a 45 p.s.i. air overpressure In FIG. 3B the curve marked addition shows the percent conversion of batch preaerated alpha-olefin versus preaeration time (and indicated peroxide number on the preaeration curve) when the preaerated samples from Example V are contacted with a stoichiometric amount of sodium bisulfite for 20 minutes as described above. The best results are obtained again with postmaximally preaerated olefins.

Hexadecenc-l preaerated by the procedure of Example III was reacted with NaHS-O under the above conditions. Results are summarized in Table I. The column marked Before Dilution gives the peroxide number of hexadecene-l preaerated in a Fischer-Porter bottle for the time shown. These solutions of preaerated hexadecene-l are diluted with alumina treated hexadecene-l to give the peroxide number shown in the column headed After Dilution. The data summarized in Table I clearly show that the best. conversion is obatined for post-maximally preaerated hexadecene-l.

TABLE I.-ADDIIION OF NaHSOa TO PREAERAIED HEXADECENE-l Peroxide Number 1 1 Titrated by Hercules Method I. 2 Alumina pretreated hexadecene-l (peroxide number less than 1) was used.

(equivalent to about 9 p.s.i. oxygen partial pressure) is applied and a gas exhaust bleed rate of 1 ft min. is obtained. The reaction is run batchwise for the contact times shown in FIG. 3B. At the end of this time the pumps are started. (After contact time of six hours the rate is one gallon per hour.) Flow rates are checked periodically by weight and adjusted if necessary. The level in the reactor is checked periodically and the outlet pump rate adjusted to maintain a level of six gallons. Product material from the first three continuous contact times is not considered to be equilibrium material and is discarded. Product from fourth contact time on is saved. A peroxide number record of a typical continuous preaeration run is given in FIG. 3B.

EXAMPLE V Batch preaeration of the alpha-olefins at 130C. in a 1*0-gallon Pfaudler reactor The batch preaeration of Chevon C -C alpha-olefins was performed in a 10-gallon Pfaudler reactor under conditions similar to those described in Example IV for continuous preaeration of Chevron C15-C13 alpha-olefins. A typical preaeration curve for batch preaeration runs in the Pfaudler reactor is shown in FIG. 3A.

EXAMPLE VI Radical addition of sodium bisulfiite to preaerated alphaolefins in a Morton flask 0.200 mole (45.8 g.) of preaerated C C alphaolefins (with various peroxide numbers) is added to a solution of 0.200 mole (20.8 g.) NaHSO in 70 ml H O contained in a 500 ml. Morton flask. To this mixture is added 70 ml. 2-propanol. The temperature is controlled at 70+1C. with a thermowatch controller while air is dispersed through the mixture through a porosity tube at a rotameter flow of 20 to cc./min. (70F. and 14.7 p.s.i. absolute). The reaction mixture is stirred at high speed with a Heller stirrer with a glass shaft and Teflon blade.

Bisulfite addition to the alpha-olefins preaerated continuously in Example IV is given in FIG. 3B. This also shows that under similar reaction conditions to those described above, the maximum bisulfite addition reaction conversion is obtained with olefins that have been preaerated past the maximum peroxide number.

EXAMPLE VII Radical addition of sodium bisulfite to preaerated Hexadecene-l in a Parr reaction vessel 0.200 mole (44.8 g.) of preaerated hex'adecene-l is added to a solution of 0.200 mole (20.8 g.) of sodium bisulfite in 50 ml. of H 0 contained in a 500 ml. Parr vessel. To this reaction mixture is added 50 ml. 2-propanol. The temperature is controlled at C. with an equilibrium pressure of 40-42 p.s.i.g. The mixture is allowed to reac in the Parr rocking apparatus for three hours.

FIG. 3C gives the conversion for various peroxide mixtures in which the peroxide mixture was obtained by diluting preaerated hexadecene-l with alumina-treated hexadecene-l to give the peroxide number shown on the abscissa. In bothcascs the hexadecene-l was preaerated according to :the procedure described in Example I. The curve marked premaximal was obtained from hexadecene-l preaerated 16.0 hours to an original undiluted premaximal peroxide number of 331. The curve marked postmaximal was obtained from hexadecene-l preaerated 30.0 hours to an original undiluted postmaxima peroxide number of 226. These results show that the olefin conversion for any preaerated olefin is proportional to the peroxide content of that particular peroxide mixture, and that the conversion is proportionately reduced by dilution with unaerated olefin.

In summary, FIGS. 3A, 3B, and 3C show dramatically that postmaxi mally preaerated olefins give much better conversions than premaxim-ally preaerated olefins having identical peroxide numbers.

EXAMPLE VIII Radical addition of NaH PO to preaerated alpha-olefins 0.150 mole (33.6 g.) hexadecene-l, (preaerated according to procedures of Example I) is added to solution containing 0.150 mole (15.9 g.) NaH PO -H o in 50 ml. water contained in a 500 ml. Parr rocking vessel. 50 ml. 2-propanol is added and the reaction mixture heated to a controlled temperature of 110i1 C. The reaction is carried out at the equilibrium solvent vapor pressure of 38-42 p.s.i. for about four hours.

Results are summarized in Table II, and again demonstrate that the better conversion obtains with postmaxilevel which is less than 95% of said maximum peroxide number and which is greater than about 100.

TABLE I[.ADDITION OF NlLIIZPO'J O PREAERATED OLEFINS Conversion, vol. percent olefin unrecovered Product isolated, a

Peroxide Number Run Number:

Premaximally preaerated 01 4718 alpha-olefin Postmaximally preaerated (In-C1 alpha-olefin 1 Gross product isolated on eavporation 01 aqueous phase and drying in vacuum over at 80 0. Infrared eoniirnis presence of alkyl phosphinate.

EXAMPLE IX Acetic acid addition to preaerated alpha-olefins A large excess of acetic acid (250 ml.) is added to 0.125 mole (28.6 g.) Chevron C C alpha-olefins preaerated (according to procedure of Example V) contained in a three-necked 500 ml. round-bottom flask and refluxed 5.5 hours at 108 C. The reaction mixture which becomes homogeneous at reflux temperature is refluxed for the time shown in Table III. Again, the better conversion is obtained with the postmaximally preaerated olefin.

2. The process of claim 1 wherein the final peroxide number is decreased to a level which is less than 95% of said maximum peroxide number and which is greater than about 100.

3. The process of claim 1 wherein the alpha olefins are mono-olefins.

4. The process of claim 1 wherein the aeration is accomplished by contacting with oxygen-containing gas at a temperature of from about 50 to 200 C.

5. The process of claim 4 wherein the temperature during aeration is from about 100 to about 175 C.

6. The process of claim 1 wherein the aeration is ac- TABLE III.ADD1TION OF ACETlC ACID TO 1 REAERATED OLEFINS Conversion to methyl 1 ilkanoic Run Peroxide esters,

Number Olelin Number grains ,08,181 Premaximally preaerated 0 -0 alpha-olefin. 361 0. 56 08,180 Postmaximally preaerated C -C1 alpha-olelin 350 1.75

Esterified with methanol before GLC analysis using authentic methyl stearate as an internal standard.

EXAMPLE X Polymerization of styrene in the presence of preaerated alpha-olefins 0.218 mole (22.7 g. 25.0 ml.) freshly distilled styrene is refluxed in 250 ml. toluene contained in a 500 ml. boiling flask for sixteen hours. The results with preand postmaximally preaerated mixtures (according to procedure of Example V) of C C Chevron alpha-olefins are shown in Table IV. The better polymerization yield is obtained with the postmaximally preaerated olefin.

complished at a pressure of from about 1.25 to about 1000 atmospheres absolute.

7. The process of claim 6 wherein the aeration is accomplished at a pressure of from about 2 to about 20 atmospheres absolute.

8. The process of claim 4 wherein the contact time between the oxygen-containing gas and the hydrocarbon is from about 0.01 to about 10 hours.

9. The process of claim 8 wherein the contact time be- TABLE IV.STYRENE POLYMERIZATION WIIII PREAERATED OLEFINS Polystyrene Grams Peroxide isolated,

Initiator added Number gm.

0. -0 alumina treated alpha-olefins 2. 00 2 0. 1 Premaximally (D -C1 alpha-olefins 2.00 423 4. 7 lostmaxirnally preaerated 0 -0 alpha-olelins 2. 00 350 5. 1

tween the oxygen-containing gas and the hydrocarbon is from about 0.1 to about 10 hours.

References Cited UNITED STATES PATENTS 3,171,864 3/1965 Clement et al 260610B 3,259,638 7/1966 Allison 260610B 3,349,122 10/1967 Segesseman 260-610B (Other references on following page) 9 10 OTHER REFERENCES BERNARD HELFIN, Primary Examiner Mair et al., Analytical Chemistry, vol. 63, No. 1, pp. W. B. LONE, Assistant Examiner 194-204 Copy Group 160.

Micrdichian Organic Synthesis, vol. II, pp. 897-899 U.S. Cl. X.R. (1960) QD262 M55 Copy Art Unit 127. 5

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION patent 3 ,549 ,708 Dated December 22 1970 Charles J Norton et a1 Inventor-(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1 line 62 "cyclohexane" should read cyclohexr line 63, "eicosadiene" should read eicosodiene Column 5 1i] Column 2 line 29 "0 5" should read 0 .05 64 "70+C" should read 70+lC Column 8 all the matte:

beginning with line 17 and including line 20 should be cancelled. In the heading to the printed specification, line I "9 Claims" should read 8 Claims Signed and sealed this 15th day of June 1971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER,

Commissioner of Paten Attesting Officer :ncm P0-\050 (10-69) u c s OMM-DC e031 

